Unique systems, methods, techniques and apparatuses of a gate drive system are disclosed. One exemplary embodiment is a drive circuit electrically coupled to a main switching device including a first inverter, a first inverter controller, an air core transformer, at least one rectifier, at least two smoothing capacitors, a current buffer stage, and a detection circuit. The first inverter controller is structured to operate the first inverter in a first mode and a second mode. The air core transformer is structured to receive the converted AC power from the first inverter. The detection circuit is structured to detect a first mode of the first inverter and a second mode of the first inverter, and operate the current buffer stage based on a detected first mode of the inverter and a detected second mode of the first inverter.
Legal claims defining the scope of protection, as filed with the USPTO.
1. A gate drive system structured to be operatively coupled to a main switching device comprising: an inverter including a plurality of inverter switching devices; an inverter controller structured to generate a plurality of inverter activation signals structured to operate the inverter switching devices so as to receive DC power, convert the received DC power to an AC power signal, and output the AC power signal; an air core transformer including a primary winding electrically coupled to the inverter so as to receive the AC power signal from the inverter, a first secondary winding, and a second secondary winding; a rectifier electrically coupled to the first secondary winding and structured to receive the AC power signal from the first secondary winding and convert the received AC power signal to DC power; two capacitors electrically coupled together at a reference voltage point and the rectifier electrically coupled in parallel to at least one of the two capacitors and such that at least one of the two capacitors receives DC power from the rectifier; a current buffer stage electrically coupled in parallel to the two capacitors, including an output node, and structured to receive DC power from the two capacitors, convert the DC power to a PWM signal including a bipolar output voltage, and output the PWM; and a detection circuit electrically coupled to the second secondary winding and structured to receive the AC power signal from the first secondary winding, sample the received AC power signal, generate at least one current buffer stage activation signal using the AC power samples, and transmit the at least one current buffer stage activation signal to the current buffer stage.
2. The gate drive system of claim 1 comprising a second rectifier, wherein one of the two capacitors is electrically coupled in parallel to the rectifier and the other capacitor is electrically coupled in parallel to the second rectifier.
3. The gate drive system of claim 1 wherein the AC power signal includes a repeating pattern of a first component and a second component, wherein the first component is an AC signal with a frequency greater than 300 kHz.
4. The gate drive system of claim 1 , wherein the output node and reference voltage point are electrically coupled to a gate and a source of the main switching device such that the main switching device receives a PWM signal with bipolar output voltage from the current buffer stage.
5. The gate drive system of claim 3 wherein the second component of the AC power signal is a zero voltage signal.
6. The gate drive system of claim 3 wherein the repeating pattern of the first component and the second component is structured such that the frequency of the repeating pattern is at most 100 kHz.
7. The gate drive system of claim 3 wherein the detection circuit is structured to detect the repeating pattern of the first component of the AC power signal and the second component of the AC power signal, and generate the at least one current buffer stage activation signal using the detected repeating pattern.
8. A drive circuit electrically coupled to a main switching device comprising: an inverter including a plurality of switching devices; an inverter controller structured to operate the inverter in a first mode and a second mode so as to receive DC power, convert the DC power to AC power, and output the AC power; an air core transformer structured to receive the converted AC power from the inverter; at least one rectifier structured to receive AC power from the air core transformer, convert the AC power to DC power, and output the DC power; at least two smoothing capacitors electrically coupled with the at least one rectifier and electrically coupled at a reference voltage point; a current buffer stage including an output node, electrically coupled in parallel to the smoothing capacitors, and structured to receive DC power from the at least one rectifier; and a detection circuit structured to detect a first mode of the inverter and a second mode of the inverter and operate the current buffer stage based on the detected first mode of the inverter and the detected second mode of the inverter.
9. The drive circuit of claim 8 wherein the plurality of switching devices of the inverter are gallium nitride (GaN) switching devices.
10. The drive circuit of claim 8 wherein the inverter being operated in the first mode is structured to generate AC power with a frequency greater than 300 kHz.
11. The drive circuit of claim 8 wherein the inverter controller is structured to operate the inverter in a repeating pattern of the first mode and the second mode, the repeating pattern having a frequency less than or equal to 100 kHz.
12. The drive circuit of claim 8 wherein the main switching device is a silicon carbide switching device.
13. The drive circuit of claim 8 wherein the reference voltage point and the output node are electrically coupled to the main switching device.
14. The drive circuit of claim 8 comprising a resonant capacitor electrically coupled between at least one of the inverter and the air core transformer, between at least one rectifier and the air core transformer, and between the detection circuit and the air core transformer, the resonant capacitor structured such that the inverter is resonantly coupled to the at least one rectifier during gate circuit operation.
15. The drive circuit of claim 13 wherein the reference voltage point and the output node are electrically coupled to the main switching device by way of at least one of a gate resistance, an active miller clamp, and a sensor.
16. The drive circuit of claim 15 wherein the sensor is structured to measure electrical characteristics of the gate circuit and provide the measurements to the inverter controller, and wherein the inverter controller is structured to operate the inverter using the measurements received from the sensor.
17. A method for operating a switching device comprising: converting DC power to an AC power signal with a first converter, the AC power signal including a combined pattern comprising a first component and a second component; providing the AC power signal to an air core transformer; receiving, with a rectifier, the AC power signal from the air core transformer; converting the AC power signal received from the air core transformer to DC power using the rectifier; sampling the AC power signal; detecting the first component and the second component using the AC power signal samples; generating an activation signal structured to toggle a set of switches of a second converter in response to detecting a transition from the first component to the second component; generating a PWM signal including bipolar output voltage using the second converter, the activation signal, and the DC power from the rectifier; and providing the PWM signal to a gate of the switching device.
18. The method of claim 17 wherein the first component of the AC power signal is a 0V signal and the second component is an AC signal with a frequency of at least 10 Mhz.
19. The method of claim 17 comprising providing the PWM signal with bipolar output voltage generated with the current buffer stage to a source of the switching device.
Cooperative Patent Classification codes for this invention. Click any code to explore related patents in that topic.
August 2, 2016
July 3, 2018
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